S mount is like a high mount, but its like...ur body is not facing foward its to the side a lil. your legs are shaped of an S.

nomral high mount:
both knees under both armpits, you face foward, you lean foward

S mount (leaning to right side)
both knees bent. your body is facing a lil to the your right and leaning to your right. left knee up to the guys armpit. your right leg had been rotated so the inner thigh is facing ceiling, and the bottom guys left arm is "loaded" onto this right leg. *if you're not flexible, ur right ass would feel intense stretching.* the result is the bottom guy's upper body, shoulders and above, are very tight in your hips, and you can armbar easier (than if from a mount). armbar can be done to either arm from this position, but the way it's set up, its easier to armbar the left arm since youre back if facing the left. if you wanna do the right arm u gotta do adjustments first.

**** your the second person who has said that about me. Considering I'm older than Tito I'll just switch that around. Now that I know what you mean by the S mount I love that mount over the traditional BJJ mount because of mobility. I prefer side control over mount because of submission accessability. The S mount allows for quicker transitions although it does secure a pin for control.